Trying to ADD SNMP after Host created

[anjoze]

I'm taking my first steps with Zabbix and need some guidance.

I started by creating a Host group called: SERVERS

I created a discovery rule called SERVERS Discovery, with the following checks:
ICMP ping
Zabbix agent "system.uname"

Then, in Alerts -> Actions -> Discovery Actions, I created an action with the conditions:

A Discovery object equals Device
B Discovery rule equals SERVERS Discovery
C Discovery status equals Up

Operations:
Add to host groups: SERVERS
Remove from host groups: Discovered hosts

Everything went well and the servers found went to the created group.

My problem starts here.
What I want is to include SNMP info to gather more information about Hosts that have already been discovered and that have the SNMP protocol enabled.

Then, I wanted to add SNMP.
I've tested with one server.
The command: snmpget -On -v2c -cpublic 192.168.1.10 SNMPv2-MIB::sysName.0
returned the Hostname with the following MIB:
SNMPv2 Agent ".1.3.6.1.2.1.1.5.0"

I edited the rule I created before (SERVERS Discovery) and added to the Checks:

SNMPv2 Agent
Port: 161
SNMP community: public
SNMP OID: .1.3.6.1.2.1.1.5.0

I waited the necessary time but there was no change.
I changed the rule:

Hostname: SNMPv2 Agent ".1.3.6.1.2.1.1.5.0"

I waited the necessary time but there was no change.
I created a new Action (Name: ADD_SNMPtoSERVERS ):

Conditions:
Discovery check equals VLAN 300 Network Servers: SNMPv2 agent ".1.3.6.1.2.1.1.5.0"
Operations:
Link Models: Generic by SNMP

I waited the necessary time but there was no change.

Do I have to delete the Server for it to be recreated again with the new actions?

Thanks for any help